This invention relates to a light-sensitive silver halide photographic material, more particularly to a light-sensitive silver halide photographic material improved in antistatic performance and also improved in storability without accompaniment of lowering in sensitivity, which can give images with high sensitivity, high contrast as well as high covering power.
Metallic silver which is indispensable as the starting material for the light-sensitive silver halide photographic material is reducing its supply, while it is demanded in various industrial fields, and attempts of silver saving in light-sensitive silver halide photographic materials have been actively done.
Also, with respect to performances of the light-sensitive silver halide photographic material, various requirements have been made, and particularly in a high sensitivity light-sensitive silver halide photographic material with stable photographic performances has been sought after. Particularly, in light-sensitive materials for X-ray, for alleviating the X-ray exposure dose to human bodies, those with higher sensitivity have been demanded, and yet light-sensitive photographic materials of high image quality have been sought after.
As a method to obtain high sensitivity and yet effect silver saving, U.S. Pat. Nos. 2,996,382 and 3,178,282 disclose the method in which a photographic image with high sensitivity, high contrast and high covering power is obtained by using a light-sensitive silver halide photographic material having surface latent image type silver halide grains and fine silver halide grains, having fogged nuclei internally of the grains, exsited adjacent to each other.
However, this method was poor in storability, particularly storability under high temperature, high humidity conditions, thus having the drawbacks that increased fog and lowering in sensitivity will occur.
On the other hand, since light-sensitive photographic materials generally comprise a support having electrical insulation and photogrpahic layers, static charges will be frequently accumulated by receiving contact friction or peeling between the same kind or different kinds of materials during production steps and usage of light-sensitive photographic materials. The static charges accumulated will cause many troubles, and the most crucial obstacle is discharging of the accumulated static charges before development processing which results in exposure of the light-sensitive emulsion layer to form dot-like spots or dentrite-like or feather-like line splotches when subjected to development processing. This is the so-called static mark, which will remarkably impair or sometimes lose entirely the commercial value of a photographic film.
For example, when said static mark appears in an X-ray film for medical or industrial use, it may lead to a very dangerous judgement. Also, when it appears in a color film, microfilm, etc., it may lead to defect of an image information.
As techniques for improvement of antistatic property of films, there have been known a large number of techniques in the art such as use of a compound obtained by addition copolymerization of glycidol and ethylene oxide with a phenol-aldehyde condensate as disclosed in Japanese Unexamined Patent Publication No. 56220/1976, combinations of a lanolin type ethylene oxide adduct and an alkali metal salt and/or an alkaline earth metal as disclosed in Japanese Unexamined Patent Publication No. 145022/1978, a water-soluble inorganic chloride and a matte agent (Japanese Patent Application No. 69242/1979), etc. However, many of these techniques which can improve antistatic characteristic will have rather deleterious effects on storability.
On the other hand, when antistatic agent conventionally used in the prior art are used, storability does not change, or may be rather worsened.
For improvement of storability, many heterocyclic compounds, typically 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 3-methyl-benzothiazole, 1-phenyl-5-mercaptotetrazole, many compounds such as hydrous silver compounds, mercapto compounds, metal salts, etc. have been known, but all of them had the drawback of accompaniment of lowering in sensitivity.